Differential evolution with topographical mutation applied to nuclear reactor core design

• We introduce a new differential evolution variant with topographical mutation.
• The topographical heuristic may be applied in several approaches.
• The problem, a nuclear reactor core design optimization, is highly multimodal.
• We give practical directions to those interested in using the new algorithm.

The nuclear reactor core design optimization problem consists in adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the average peak-factor in a three-enrichment-zone reactor, considering restrictions on the average thermal flux, criticality and sub-moderation. This problem is highly multimodal, requiring optimization techniques that overcome local optima, which can be done achieving a balance between the exploration of the search space and the exploitation of its most promising areas. In order to do so, we introduce a variant of the differential evolution algorithm (DE) with a new mutation operator based on a topographical heuristic introduced in the early nineties, as part of a global optimization method. The new method, called TopoMut-DE, is favorably compared against the canonical version of differential evolution, and even to state-of-the-art variants, namely Opposition-Based DE and Trigonometric-Mutation Operator DE. As the problem attacked is quite challenging, the results show the potential of TopoMut-DE to be applied to other nuclear science and engineering problems.